Ovulate early?

For the last 4 cycles I have been pretty regular. Cycle is 35-37 days. Ovulation is generally day 21-23. Normally I start testing as soon as period ends and stop when I get peak around the 3 week mark. Never peaked or even got high outside of this window. This month I decided to let off the pressure with baby making. I didnt do ovulation testing obsessively and was focus in sex for enjoyment. I have been obsessive enough about my cycle for 4 months I know my ovulation symptoms without testing. Noticed these symptoms yesterday so I took a test. High yesterday and definitely a peak today (confirmed with a digital test). Its 10 days early from expected ovulation time. WHAT THE HELL?!?! I'm not upset, but I am confused... I plan to keep testing until my usual window to see if this is a odd spike or legit.